ios - how - swift uicollectionview data source

Fallo de aserción en UITableViewController

Question

Estoy tomando la clase de iOS iTunes U Stanford y estoy trabajando en una de las tareas para crear una pequeña aplicación de Flickr. Recibo un error que parece que no puedo depurar, lo que aparece como

* Fallo de aserción en - [UITableView _configureCellForDisplay: forIndexPath:], /SourceCache/UIKit_Sim/UIKit-2280.1/UITableView.m:5336 2012-08-03 10: 59: 24.596 Asignación 4 [4611: c07] c07] (null) libc ++ abi.dylib: termina llamado lanzando una excepción

Mi código para el tableviewcontroller en cuestión:

#import "PlacesPhotosTableViewController.h"

@interface PlacesPhotosTableViewController ()
@property (nonatomic) NSDictionary *placeToDisplay;
@property (nonatomic) NSArray *photosInPlace;
@end

@implementation PlacesPhotosTableViewController
@synthesize placeToDisplay = _placeToDisplay;
@synthesize photosInPlace = _photosInPlace;

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (id)init
{
    self = [super init];

    return self;
}

- (id)initWithPlace:(NSDictionary *)place
{
    self = [self init];
    if (self)
    {
        self.placeToDisplay = place;
    }

    return self;
}

- (NSArray *)photosInPlace
{
    if (_photosInPlace == nil)
    {
        _photosInPlace = [FlickrFetcher photosInPlace:self.placeToDisplay maxResults:50];
    }

    return _photosInPlace;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSLog([self.placeToDisplay valueForKeyPath:@"description._content"]);

    // Uncomment the following line to preserve selection between presentations.
    // self.clearsSelectionOnViewWillAppear = NO;

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Table view data source


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
#warning Incomplete method implementation.
    // Return the number of rows in the section.
    return [self.photosInPlace count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Photos";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    NSString *string = [[self.photosInPlace objectAtIndex:indexPath.row] valueForKeyPath:@"description._content"];

    cell.textLabel.text = string;

    return cell;
}

Answer 1

Esta linea aqui

static NSString *CellIdentifier = @"Photos";

¿Coincide esto con el identificador de celda en tu guión gráfico? ¡Encontré que estos no coincidentes fueron la causa del problema para mí!

Answer 2

Me enfrenté al mismo problema y lo resolví porque olvidé agregar.

return cell;

ahora esta resuelto

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    if(tableView==notiTblView){

        NSLog(@"TABLE NEW");

        static NSString *cellIdentifier = @"MenuCell";
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
        UIImageView *imageview;
        UILabel *label;
        UILabel *lblDetail;

        if(cell == nil)
        {

            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault   reuseIdentifier:cellIdentifier];
            imageview=[[UIImageView alloc]initWithFrame:CGRectMake(8, 3,30, 37)];
            label=[[UILabel alloc]initWithFrame:CGRectMake(70, 10, 100, 20)];
            lblDetail=[[UILabel alloc]initWithFrame:CGRectMake(70, 35, 100, 30)];
            lblDetail.numberOfLines=3;

            imageview.tag=100;
            label.tag=101;
            lblDetail.tag=102;

            label.textColor=[UIColor blackColor];
            label.font=[UIFont systemFontOfSize:15];
            label.backgroundColor=[UIColor clearColor];

            lblDetail.textColor=[UIColor grayColor];
            lblDetail.font=[UIFont systemFontOfSize:13];
            lblDetail.backgroundColor=[UIColor clearColor];


            [cell.contentView addSubview:imageview];
            [cell.contentView addSubview:label];
            [cell.contentView addSubview:lblDetail];

        }

        cell.selectionStyle=UITableViewCellSelectionStyleNone;
        UIImageView *img=(UIImageView *)[cell.contentView viewWithTag:100];
        UILabel *lbl=(UILabel *)[cell.contentView viewWithTag:101];

        NSString * stirngId = [NSString stringWithFormat:@"%@",[[notificationARRAY objectAtIndex:indexPath.row]objectForKey:@"photoID"]];

        if ([dicImages_msg valueForKey:[[notificationARRAY objectAtIndex:indexPath.row] valueForKey:@"productName"]]) {

            img.image=[dicImages_msg valueForKey:[[notificationARRAY objectAtIndex:indexPath.row] valueForKey:@"productName"]];

        }
        else
        {
            if (!isDragging_msg && !isDecliring_msg)
            {
                [dicImages_msg setObject:[UIImage imageNamed:@"timthumb.jpg"] forKey:[[notificationARRAY objectAtIndex:indexPath.row] valueForKey:@"productName"]];
                [self performSelectorInBackground:@selector(download_Noti_image:) withObject:indexPath];
            }
            else
            {
                img.image=[UIImage imageNamed:@"timthumb.jpg"];
            }
        }

        lbl.text=[[notificationARRAY objectAtIndex:indexPath.row] objectForKey:@"memberName"];
        lbl.text=[[notificationARRAY objectAtIndex:indexPath.row] objectForKey:@"memberName"];

        return cell;

       /* static NSString *MyIdentifier = @"MyIdentifier";
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier] ;
            cell.selectionStyle=UITableViewCellSelectionStyleNone;
            }
        cell.textLabel.text=[[notificationARRAY objectAtIndex:indexPath.row] objectForKey:@"memberName"];
        return cell;*/

   }else{
       static NSString *cellIdentifier = @"MenuCell";
       TblCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
       if (cell==nil) {
           cell = [[TblCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
            }

       NSLog(@"arr..in table..%@",PostedItem);
       cell.selectionStyle=UITableViewCellSelectionStyleNone;

       if([[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"productType"] isEqualToString :@"Video"]){
           cell.postedimage.image=[UIImage imageNamed:@"play_icon.png"];
       }else{

           if ([dicImages_msg valueForKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"productName"]]) {

               cell.postedimage.image=[dicImages_msg valueForKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"productName"]];

           }else
            {
                if (!isDragging_msg && !isDecliring_msg)
                    {
                        [dicImages_msg setObject:[UIImage imageNamed:@"timthumb.jpg"] forKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"productName"]];
                        [self performSelectorInBackground:@selector(downloadImage_3:) withObject:indexPath];
                    } else
                        {
                            cell.postedimage.image=[UIImage imageNamed:@"timthumb.jpg"];
                        }
            }

       }
//*******************User image
    if ([dic_usrImg valueForKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"thumbUrl"]]) {

        cell.profileImage.image=[dic_usrImg valueForKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"thumbUrl"]];

    }
    else
    {
        if (!isDragging_msg && !isDecliring_msg)
        {
            [dic_usrImg setObject:[UIImage imageNamed:@"timthumb.jpg"] forKey:[[PostedItem objectAtIndex:indexPath.row] valueForKey:@"thumbUrl"]];
            [self performSelectorInBackground:@selector(downloadImage_IMAGE4:) withObject:indexPath];
        }
        else
        {
            cell.profileImage.image=[UIImage imageNamed:@"timthumb.jpg"];
        }
    }
//********************************
    [cell.btnImage setTag:100000+indexPath.row];
    [cell.btnImage  addTarget:self action:@selector(Shopw_feedImg:) forControlEvents:UIControlEventTouchUpInside];
//***************
    cell.postedimage.tag=indexPath.row;
    [cell.postedimage setUserInteractionEnabled:YES];
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onImageClick:)];
    [tap setNumberOfTouchesRequired:1];
    [tap setNumberOfTapsRequired:1];
    [tap setDelegate:self];
    [cell.postedimage addGestureRecognizer:tap];
    cell.membername.text=[[PostedItem objectAtIndex:indexPath.row] objectForKey:@"userName"];
    [cell.membername sizeToFit];
    //[[PostedItem objectAtIndex:indexPath.row] objectForKey:@"memberID"];  
    cell.productName.text= [[PostedItem objectAtIndex:indexPath.row]objectForKey:@"photoTitle"];
    //@"hello this is a test doviumbmvbhdf asx";
   // with new sffhy dgftn tun dgh ";
  //  NSLog(@"Str Length...%d",[cell.productName.text length]);
    if ([cell.productName.text length]>38) {

        NSLog(@"greater then...%@",cell.productName.text);
         cell.productName.numberOfLines=2;
        CGRect frame=cell.postedimage.frame;
        frame.origin.y=130;
        cell.postedimage.frame=frame;
        CGRect Prdctframe=cell.productName.frame;
        frame.size.height=40.0f;
        cell.productName.frame=Prdctframe;
        //cell.postedimage.frame.origin.y=115.0f;
    }//[[PostedItem objectAtIndex:indexPath.row]objectForKey:@"photoTitle"];
      //@"szfgfgbjmghufho stdogb ryt;o esftesi rdetg ry ry ry ";//
    else
    {
        cell.productName.numberOfLines=1;
        CGRect frame=cell.postedimage.frame;
        frame.origin.y=110;
        cell.postedimage.frame=frame;
        CGRect Prdctframe=cell.productName.frame;
        Prdctframe.size.height=20.0f;
        cell.productName.frame=Prdctframe;
          NSLog(@"less then...");
    }

    //[cell.productName sizeToFit];
 //   cell.profileImage.image=[UIImage imageNamed:@"timthumb.jpg"];
    return cell;
   }

}

Answer 3

No estás creando celda en método

tableView:cellForRowAtIndexPath:

Solo reutilizando la celda de este método que devuelve nil inicialmente.

Tienes que crear la celda por este código dado a continuación en su método.

if(cell==nil){

    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault 
reuseIdentifier:CellIdentifier] autorelease];

}

Answer 4

CellIdentifier Apuesto a que su cellForRowAtIndexPath está devolviendo nil .

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath     *)indexPath
{
    static NSString *CellIdentifier = @"Photos";

    /** NOTE: This method can return nil so you need to account for that in code */
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    // NOTE: Add some code like this to create a new cell if there are none to reuse
    if(cell == nil)
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];

    }

    NSString *string = [[self.photosInPlace objectAtIndex:indexPath.row]     valueForKeyPath:@"description._content"];

    cell.textLabel.text = string;

    return cell;
}

Probablemente esa sea la razón por la que [UITableView _configureCellForDisplay:forIndexPath:] está fallando ... porque cellForRowAtIndexPath está devolviendo un valor nulo y luego configureCellForDisplay está esperando un UITableViewCell .